Artificial Flagstone For Providing A Surface With A Natural Random Look

ABSTRACT

An artificial flagstone for use in combination with other similar flagstones for covering a surface with a natural random look, the flagstone having a generally hexagonal body comprising a first, second, third, fourth, fifth and sixth consecutive vertices; a first pair of generally congruent irregularly-shaped first and second sides extending radially from the first vertex and being rotationally spaced from each other by an angle α of approximately 120°; a second pair of generally congruent irregularly shaped third and fourth sides extending radially from the third vertex and being rotationally spaced from each other by an angle β of approximately 120°; a third pair of generally congruent irregularly shaped fifth and sixth sides extending radially from the fifth vertex and being rotationally spaced from each other by an angle ω of approximately 120°; wherein the sides of each of the first, second and third pair of sides have at least one split deviation along their length and are respectively rotational images of each other, whereby in use in combination with other flagstones, each one of the sides is matingly engageable with the sides of an equivalent pair of sides of a neighbouring flagstone.

FIELD OF THE INVENTION

The present invention relates generally to the field of artificialstones or flagstones for laying out pavements or for covering a wallsurface, and is more particularly directed to such stones giving theresulting pavement or wall surface a natural-looking appearance.

BACKGROUND OF THE INVENTION

It is worth mentioning that the expressions “stone” and “flagstone” areused throughout the present description without distinction to define aflat slab of stone used as a paving or building material. Artificialstones often made of concrete are well-known to lay out pavements orcovering wall surfaces on residential or commercial properties, forexample defining the surface of walkways or patios. Such stones areadvantageously relatively inexpensive to make, as opposed to naturalcarved flagstones, but the resulting pattern is often repetitive or haswhat is called in this field an unnatural “linear line effect”. Greatefforts are therefore being made to design artificial stones whichprovide a more natural look, creating the effect of old worldcraftsmanship, while still retaining the ease of their manufacture.

One example of a prior art artificial flagstone is the flagstonemarketed under the trademark Kusel-Form. One drawback however with thatprior art flagstone, which is provided with regular segments, is that itstill does not provide a satisfactory old natural look. It still looksartificial.

Other attempts have been made in the past to develop sets of artificialstones comprising stones of different shapes used in combination witheach other for paving a surface. The natural random look in those casesis obtained by combining artificial stones of different shapes. A majordrawback however with those sets is that it often becomes a real puzzlefor a user to install and combine those stones in a proper way.

Thus, there is still presently a need for an artificial flagstone thatprovides the real natural random look, long sought after, while at thesame time being easy to manufacture at a reasonable cost and easy toinstall for any unskilled person.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an artificial flagstonethat satisfies the above-mentioned need.

In accordance with the present invention, that object is achieved withan artificial flagstone for use in combination with other ones of saidartificial flagstones for covering a surface with a natural random look.The flagstone has a generally hexagonal body comprising:

-   -   a first, second, third, fourth, fifth and sixth consecutive        vertices;    -   a first pair of generally congruent irregularly-shaped first and        second sides extending radially from the first vertex and being        rotationally spaced from each other by an angle α of        approximately 120°;    -   a second pair of generally congruent irregularly shaped third        and fourth sides extending radially from the third vertex and        being rotationally spaced from each other by an angle β of        approximately 120°;    -   a third pair of generally congruent irregularly shaped fifth and        sixth sides extending radially from the fifth vertex and being        rotationally spaced from each other by an angle ω of        approximately 120°;        wherein the sides of each of the first, second and third pair of        sides have at least one split deviation along their length and        are respectively rotational images of each other, whereby in use        in combination with the other flagstones, each one of the sides        is matingly engageable with the sides of an equivalent pair of        sides of a neighbouring flagstone.

Advantageously, the present invention makes it possible to obtain apavement with a real natural random look with no “linear line effect” bysimply using a plurality of artificial flagstones having all the sameshape. In other words, a single module is sufficient to create amultitude of different designs. There is no need to use different shapesof flagstone to obtain the sought after natural look. Also, the splitdeviation provided on each side provides an irregular profile that givesthe flagstone a more natural look.

The flagstone according to the invention can advantageously be used forcreating patio, pathways, sidewalks or stepping stones. Its asymmetricalshape makes the flagstone the ideal material for creating a greatvariety of designs. With its six irregular sides, the flagstone fitsperfectly together, since the flagstone is provided with matinglyengageable stone, the end result is extremely stable. Also, for adifferent look, you can leave wider joints between them and fill thevoids with grass.

The present invention is also very advantageous for a manufacturer,since the production of the flagstones requires only a single shape forthe mould used for moulding the flagstones.

In accordance with a preferred embodiment, the sides of the second pairof sides are generally congruent to the sides of the third pair ofsides.

Also preferably, the fourth and fifth sides, which extend radially fromthe fourth vertex, are rotationally spaced from each other by an angle θof approximately 90°.

Still preferably, the sides of the first pair are approximately half thelength of the sides of the second and third pair of sides.

Also preferably, each of the sides has a chiseled upper edge to imitatea Paleolithic stone, and the top face of the stone has a texture thatimitates a natural flagstone.

The present invention also concerns a paving covering a surface, thepaving comprising a plurality of randomly laid identical flagstones,each of the flagstones being as described hereinabove.

Advantageously, the flagstones of the present invention can easily belaid out to form a pavement or a wall surface where no straight linesand hardly any repetition can be seen, giving as a result, the look ofold world craftsmanship.

Further aspects and advantages of the present invention will be betterunderstood upon reading of preferred embodiments thereof with respect tothe appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are respectively schematic top and partial side views ofan artificial flagstone according to a first preferred embodiment of theinvention.

FIGS. 2A and 2B schematically illustrates two possible arrangementsshowing the three possible relative orientations of the flagstone ofFIG. 1A when laid out to form a pavement or for covering a wall surface,FIG. 2C is an enlargement of zone 2C of FIG. 2A.

FIG. 3 schematically shows a section of a pavement made of artificialflagstones as shown in FIG. 1A; FIG. 3A is an enlargement of zone 3A ofFIG. 3.

FIG. 4 shows a plurality of laid out flagstones as shown in FIGS. 1A and1B, identified according to their relative orientation.

FIG. 5 is

a schematic side view of piled up flagstones of different texturesaccording to another aspect of the invention.

FIG. 6 is a perspective view of a flagstone having a top surfaceprovided with deep joints according to another preferred embodiment ofthe invention.

FIG. 7A is a schematic top view of an artificial stone according to asecond preferred embodiment of the invention and FIG. 7B schematicallyshows a section of a pavement made of artificial flagstone as shown inFIG. 7A.

FIG. 8A is a schematic top view of an artificial stone according to athird preferred embodiment of the invention; FIG. 8B schematically showsa section of a pavement made of artificial flagstone as shown in FIG.8A.

FIG. 9A is a schematic top view of an artificial stone according to afourth preferred embodiment of the invention; FIG. 9B schematicallyshows a section of a pavement made of artificial flagstone as shown inFIG. 9A.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

In the following description, similar features in the drawings have beengiven similar reference numerals and in order to lighten the figures,some elements are not referred to in some figures if they were alreadyidentified in a preceding figure.

Referring to either one of FIGS. 1A, 7A, 8A and 9A, the outline of anartificial flagstone 10 according to the invention is illustrated. Theillustrated flagstone 10 has a generally hexagonal body with six (6)consecutive vertices 1 to 6 and six (6) sides 12 a to 12 f, definingthree pairs 12 a-12 b, 12 c-12 d and 12 e-12 f of mutually engageablesurfaces. The first and second sides (12 a-12 b) extend radially fromthe first vertex 1 and are rotationally spaced from each other by anangle α of approximately 120°. The third and fourth sides (12 c-12 d)extend radially from the third vertex 3 and are rotationally spaced fromeach other by an angle β of approximately 120°. Finally, the fifth andsixth sides (12 e-12 f) extend from the fifth vertex 5 and arerotationally spaced from each other by an angle ω of approximately 120°.It can also be appreciated that the sides of each of the first, secondand third pair of sides have at least one split deviation 14 b alongtheir length, and are respectively rotationally images of each other,whereby in use in combination with identical flagstones, each one of thesides is matingly engageable with the sides of an equivalent pair ofsides of a neighbouring flagstone, as shown for example in FIGS. 4, 7B,8B and 9B. In each of the preferred embodiments illustrated, each sidecomprises only one split deviation which divides the sides in threesegments, 14 a, 14 b and 14 c.

More particularly, each side has a specific shape along its length whichis formed of three end-to-end segments: a first generally straightsegment 14 a, followed by the split deviation 14 b and a secondgenerally straight segment 14 c which extends along an axissubstantially parallel to the first straight segment 14 a. Whileconserving this general profile, the sides 12 a to 12 f are howeverslightly irregular, to give the flagstone a more natural looking aspect.

The sides of a given pair have mating profiles, that is the profile ofside 12 b rotated by 1200 mates (in other words conforms or fits) withthe profile of side 12 a, and similarly for sides 12 c-12 d, and 12 e-12f. It will be observed that in this manner, the sides of each pairrespectively project inwardly and outwardly with respect to the body ofthe flagstone.

As can be appreciated, in the first, third and fourth preferredembodiments (FIGS. 1, 8A and 9A, the sides of the second pair of sides(12 c-12 d) are generally congruent (same length) to the sides of thethird pair of sides (12 e-12 f).

It is worth mentioning that the angle between the sides forming thesecond, fourth and sixth vertices can take numerous values as long astheir sum equals 360°. As for example, in the preferred embodiment shownin FIG. 1A, the sides forming the second and sixth vertices, that is tosay, sides 12 b and 12 c and sides 12 a and 12 f, form an angle equal to135°, whereas the angle separating the sides (12 d, 12 e) forming thefourth vertex is equal to 90°.

In the preferred embodiment shown in FIG. 7A, the angle between thesides 12 b-12 c forming the second apex 2 is equal to 93.58°, the sides12 d-12 e forming the fourth apex 4 form an angle of 80.88° and theangle between the sides 12 f-12 g forming the sixth apex 6 is 185.54°.As can be appreciated, the same angles in the preferred embodimentsshown in FIGS. 8A and 9A take other values.

Referring to FIG. 1B, a section of the flagstone of FIG. 1A is shown,where it can be seen that the side walls and top surface thereof arealso irregular.

The characteristics of a pavement made of flagstones as described abovewill now be described with reference to FIGS. 2 to 5, and 7B, 8B, 9B. Itwill be appreciated that all of the flagstones of a pavement are thesame, but still create a visually “random” effect in which no straightlines can be seen. As illustrated more particularly in FIGS. 2A, 2B and4, each flagstone is laid out relative to the others in one of threeorientations A, B, and C. In every case, side 12 a of one flagstone isadjacent to side 12 b of another, and the same is true for sides 12 c-12d and 12 e-12 f. Spaces of about 2 to 7 mm in width can be seen betweenadjacent flagstones due to the irregularity of the side edges (see moreparticularly FIG. 3A).

Referring to FIG. 5, there are shown possible patterns for the topsurface of the artificial stones of the invention. The top surface ispreferably given a texture which imitates real flagstones or the like,and the side edges have chiseled upper edges to imitate a Paleolithicstone. Preferably, the top surface of the stones has several regions ofthe same height, facilitating stacking of the stones.

Referring to FIG. 6, there is shown an artificial flagstone inaccordance with yet another preferred embodiment of the invention. Inthis embodiment, a flagstone of the profile described above has a topsurface 16 provided with deep joints 18 therein. The deep joints 18preferably extend through a portion of the height of the flagstone, sothat when the stone is laid out, it gives the visual impression of anarrangement of smaller stones, while still retaining the advantages ofhandling only a larger block. In the illustrated embodiment, the deepjoints separate the stone into five sections 20A-20E of various shapesand sizes, and are arranged so that they intersect the sides 12 a-12 fof the stone either at the joints of two sides or at the sloped segmentof a given side. It will be observed from FIG. 6 that with thisembodiment, the resulting pavement will seem even more random to theeye. The deep joints 18 may in addition be filled with sand or anotherfilling material, giving an even more natural look to the pavement.

In another aspect of this embodiment, the stone may preferably bebreakable along the deep joints 18. This allows breaking off one or moreof the stone sections 20. Advantageously, as the broken off stonesection will still have at least one side following one of the profiles12 a-12 f of the general stone, it will still be possible to matinglyengage it with the side of another stone having the matching profile.For example, section 20A having a side 12 e, it could be laid about theside 12 f of a similar stone in the same mating engagement describedabove. This particular embodiment is particularly advantageous toprovide a more regular profile at the edge of a pavement, particularlyfor narrow patterns such as walkways. A side section 20 outwardlyprojecting at an edge of the walkway may be broken off and used to filla hole at another portion of the edge or at any appropriate location.

Now referring to FIGS. 2A and 2B, there is shown an artificial flagstonein accordance with a still further preferred embodiment of theinvention. In this embodiment, the perimeter of the flagstone isidentical to any one of the above-described flagstones. It is howeverpreferably provided with distinctive markers (22 a to 22 f) used forguiding the laying out of a plurality of flagstones on a surface. Morepreferably, these distinctive markers (22 a to 22 f) are located at thevertices of the flagstone and consist of thin generally plate membersprotruding from the vertices.

As can be appreciated, the distinctive markers 22 b, 22 d, 22 f locatedat the second, fourth and sixth vertices 2, 4, 6 are substantiallyidentical to each other, whereas the distinctive markers 22 a, 22 c, 22e located at the first, third and fifth vertices 1, 3, 5 are differentfrom each other and different from the markers of the second, fourth andsixth vertices.

Even more preferably, the plate-shaped member 22 a of the first vertex 1comprises four grooves 24. Two of these grooves are located on the firstside 12 a and the other two grooves 24 are located on the second side 12b, whereas the plate-shaped member 22 e of the fifth vertex 5 comprisestwo grooves, one on each of the fifth and sixth sides 12 e-12 f,respectively.

Therefore, for combining, as for example, a side 12 a with a side 12 bof a neighbour flagstone, the user just simply has to guide himself byassociating the side with identical markers with each other, as shown inFIG. 2C.

The stone according to the present invention has several advantages overprior art products. Its installation is easy, and does not generallyrequire professional skills. The resulting pavement has no “lineareffect”, that is, a person walking thereon would not see any straightline in front of him or her. It has a random look, achieved with asingle stone design.

The present invention is also advantageous over the prior art since itprovides a one piece engageable unit that can cover a surface by simplyrotating the one piece unit of 120°, as shown for example in FIGS. 2Aand 2B.

Of course, numerous modifications could be made to the embodiments abovewithout departing from the scope of the invention.

1. An artificial flagstone for use in combination with other ones ofsaid artificial flagstones for covering a surface with a natural randomlook, the flagstone having a generally hexagonal body comprising: afirst, second, third, fourth, fifth and sixth consecutive vertices; afirst pair of generally congruent first and second sides extendingradially from the first vertex and being rotationally spaced from eachother by an angle α of approximately 120°; a second pair of generallycongruent third and fourth sides extending radially from the thirdvertex and being rotationally spaced from each other by an angle β ofapproximately 120°; a third pair of generally congruent fifth and sixthsides extending radially from the fifth vertex and being rotationallyspaced from each other by an angle ω of approximately 120°; wherein thesides of at least one of said first, second and third pair of sides haveat least one split deviation along their length and are respectivelyrotational images of each other, whereby in use in combination with saidother flagstones, each one of said sides is matingly engageable with thesides of an equivalent pair of sides of a neighbouring flagstone.
 2. Theflagstone as claimed in claim 1, wherein the sides of the second pair ofsides are generally congruent to the sides of the third pair of sides.3. The flagstone as claimed in claim 2, wherein the fourth and fifthsides extend radially from the fourth vertex and are rotationally spacedfrom each other by an angle θ of approximately 90°.
 4. The flagstone asclaimed in claim 3, wherein the sides of the first pair areapproximately half the length of the sides of the second and third pairof sides.
 5. The flagstone as claimed in claim 1, wherein each of saidsides has a chiseled upper edge.
 6. The flagstone as claimed in claim 1,having a top face with a texture that imitates a natural flagstone. 7.The flagstone as claimed in claim 6, wherein the top face comprises deepjoints dividing the top face into smaller top sections.
 8. The flagstoneas claimed in claim 1, wherein the sides of said first, second and thirdpair of sides having said at least one split deviation define alongtheir length a first generally straight segment, followed by said splitdeviation and a second generally straight segment.
 9. The flagstone asclaimed in 1, wherein the sides of each of the first, second and thirdpair of sides have said at least one split deviation.
 10. The flagstoneas claimed in claim 1, wherein the second side and third side arerotationally spaced from each other by an angle of approximately 135°;and the sixth side and first side are rotationally spaced from eachother by an angle of approximately 135°.
 11. The flagstone as claimed inclaim 1, wherein all of said pairs of sides have distinctive markersguiding a lay out of a plurality of said flagstone on a surface.
 12. Theflagstone as claimed in claim 11, wherein said distinctive markers arelocated at said vertices.
 13. The flagstone as claimed in claimed 12,wherein said distinctive markers consist of thin plate-shaped membersprotruding from said vertices.
 14. The flagstone as claimed in claim 13,wherein the distinctive markers located at the second, fourth and sixthvertices are substantially identical to each other, whereas thedistinctive markers located at the first, third and fifth vertices aredifferent from each other and different from the markers of the second,fourth and sixth vertices.
 15. The flagstone as claimed in claim 14,wherein the plate-shaped member of said second, fourth and sixthvertices is uniform, the plate-shaped member of the first vertexcomprising four grooves, two on each of the first and second sidesrespectively, the plate-shaped member of the third vertex being uniformand the plate-shaped member of the fifth vertex comprising two grooves,one on each of said fifth and sixth sides respectively.
 16. Theflagstone as claimed in claim 7, wherein the body of the flagstone isdivided into a bottom part devised to contact the surface to cover andan upper part topping the bottom part, the upper part having a contourline generally similar to the bottom part and a surface area smallerthan the surface area of the bottom part whereby spaces are createdbetween the upper part of adjacent flagstones covering a surface.
 17. Anartificial flagstone for use in combination with other ones of saidartificial flagstones for covering a surface with a natural random look,the flagstone having a generally hexagonal body comprising: a first,second, third, fourth, fifth and sixth consecutive vertices; a firstpair of generally congruent first and second sides extending radiallyfrom the first vertex and being rotationally spaced from each other byan angle α of approximately 120°; a second pair of generally congruentthird and fourth sides extending radially from the third vertex andbeing rotationally spaced from each other by an angle β of approximately120°; a third pair of generally congruent fifth and sixth sidesextending radially from the fifth vertex and being rotationally spacedfrom each other by an angle ω of approximately 120°; and a top facecomprising deep joints dividing the top face into smaller top sections.18. The flagstone as claimed in claim 17, wherein the sides of at leastone of said first, second and third pair of sides have at least onesplit deviation along their length and are respectively rotationalimages of each other, whereby in use in combination with said otherflagstones, each one of said sides is matingly engageable with the sidesof an equivalent pair of sides of a neighbouring flagstone.
 19. Theflagstone as claimed in claim 17, wherein the sides of the second pairof sides are generally congruent to the sides of the third pair ofsides.
 20. The flagstone as claimed in claim 19, wherein the fourth andfifth sides extend radially from the fourth vertex and are rotationallyspaced from each other by an angle θ of approximately 90°.
 21. Theflagstone as claimed in claim 20, wherein the sides of the first pairare approximately half the length of the sides of the second and thirdpair of sides.
 22. The flagstone as claimed in claim 17, wherein each ofsaid sides has a chiseled upper edge.
 23. The flagstone as claimed inclaim 17, having the top face has a texture that imitates a naturalflagstone.
 24. The flagstone as claimed in claim 18, wherein the sidesof said first, second and third pair of sides having said at least onesplit deviation define along their length a first generally straightsegment, followed by said split deviation and a second generallystraight segment.
 25. The flagstone as claimed in 18, wherein the sidesof each of the first, second and third pair of sides have said at leastone split deviation
 26. The flagstone as claimed in claim 17, whereinthe second side and third side are rotationally spaced from each otherby an angle of approximately 135°; and the sixth side and first side arerotationally spaced from each other by an angle of approximately 135°.27. The flagstone as claimed in claim 17, wherein all of said pairs ofsides have distinctive markers guiding a lay out of a plurality of saidflagstone on a surface.
 28. The flagstone as claimed in claim 27,wherein said distinctive markers are located at said vertices.
 29. Theflagstone as claimed in claimed 28, wherein said distinctive markersconsist of thin plate-shaped members protruding from said vertices. 30.The flagstone as claimed in claim 29, wherein the distinctive markerslocated at the second, fourth and sixth vertices are substantiallyidentical to each other, whereas the distinctive markers located at thefirst, third and fifth vertices are different from each other anddifferent from the markers of the second, fourth and sixth vertices. 31.The flagstone as claimed in claim 30, wherein the plate-shaped member ofsaid second, fourth and sixth vertices is uniform, the plate-shapedmember of the first vertex comprising four grooves, two on each of thefirst and second sides respectively, the plate-shaped member of thethird vertex being uniform and the plate-shaped member of the fifthvertex comprising two grooves, one on each of said fifth and sixth sidesrespectively.
 32. The flagstone as claimed in claim 17, wherein the bodyof the flagstone is divided into a bottom part devised to contact thesurface to cover and an upper part topping the bottom part, the upperpart having a contour line generally similar to the bottom part and asurface area smaller than the surface area of the bottom part wherebyspaces are created between the upper part of adjacent flagstonescovering a surface.
 33. An artificial flagstone for use in combinationwith other ones of said artificial flagstones for covering a surfacewith a natural random look, the flagstone having a generally hexagonalbody comprising: a first, second, third, fourth, fifth and sixthconsecutive vertices; a first pair of generally congruent first andsecond sides extending radially from the first vertex and beingrotationally spaced from each other by an angle α of approximately 120°;a second pair of generally congruent third and fourth sides extendingradially from the third vertex and being rotationally spaced from eachother by an angle β of approximately 120°; a third pair of generallycongruent fifth and sixth sides extending radially from the fifth vertexand being rotationally spaced from each other by an angle ω ofapproximately 120°; wherein the body of the flagstone is divided into abottom part devised to contact the surface to cover and an upper parttopping the bottom part, the upper part having a contour line generallysimilar to the bottom part and a surface area smaller than the surfacearea of the bottom part whereby spaces are created between the upperpart of adjacent flagstones covering a surface.
 34. The flagstone asclaimed in claim 33, wherein the sides of at least one of said first,second and third pair of sides have at least one split deviation alongtheir length and are respectively rotational images of each other,whereby in use in combination with said other flagstones, each one ofsaid sides is matingly engageable with the sides of an equivalent pairof sides of a neighbouring flagstone.
 35. The flagstone as claimed inclaim 33, wherein the sides of the second pair of sides are generallycongruent to the sides of the third pair of sides.
 36. The flagstone asclaimed in claim 35, wherein the fourth and fifth sides extend radiallyfrom the fourth vertex and are rotationally spaced from each other by anangle θ of approximately 90°.
 37. The flagstone as claimed in claim 36,wherein the sides of the first pair are approximately half the length ofthe sides of the second and third pair of sides.
 38. The flagstone asclaimed in claim 33, wherein each of said sides has a chiseled upperedge.
 39. The flagstone as claimed in claim 33, having the top face hasa texture that imitates a natural flagstone.
 40. The flagstone asclaimed in claim 34, wherein the sides of said first, second and thirdpair of sides having said at least one split deviation define alongtheir length a first generally straight segment, followed by said splitdeviation and a second generally straight segment.
 41. The flagstone asclaimed in 34, wherein the sides of each of the first, second and thirdpair of sides have said at least one split deviation
 42. The flagstoneas claimed in claim 33, wherein the second side and third side arerotationally spaced from each other by an angle of approximately 135°;and the sixth side and first side are rotationally spaced from eachother by an angle of approximately 135°.
 43. The flagstone as claimed inclaim 33, wherein all of said pairs of sides have distinctive markersguiding a lay out of a plurality of said flagstone on a surface.
 44. Theflagstone as claimed in claim 43, wherein said distinctive markers arelocated at said vertices.
 45. The flagstone as claimed in claimed 44,wherein said distinctive markers consist of thin plate-shaped membersprotruding from said vertices.
 46. The flagstone as claimed in claim 45,wherein the distinctive markers located at the second, fourth and sixthvertices are substantially identical to each other, whereas thedistinctive markers located at the first, third and fifth vertices aredifferent from each other and different from the markers of the second,fourth and sixth vertices.
 47. The flagstone as claimed in claim 46,wherein the plate-shaped member of said second, fourth and sixthvertices is uniform, the plate-shaped member of the first vertexcomprising four grooves, two on each of the first and second sidesrespectively, the plate-shaped member of the third vertex being uniformand the plate-shaped member of the fifth vertex comprising two grooves,one on each of said fifth and sixth sides respectively.
 48. Theflagstone as claimed in claim 39, wherein the top face comprises deepjoints dividing the top face into smaller top sections.